If you do the math, having one capsuleer in a boosting ship like a Porpoise or Orca is already beneficial when your mining fleet has 3 people. With every extra person in fleet those boosts will even better.
It’s very rewarding to have fleet boosts for the entire fleet.
The only problem here seems to be that your hypothetical fleet doesn’t compensate the boosting pilot. This is a social challenge and one of the aspects that makes EVE a much more social game in my experience than most other games.
Many groups give ISK or ore to the booster.
You suggest allowing drones to compensate the booster, but not only does that require significant reworks to drones, it also has a couple of issues:
Fair compensation
My Hulk mines 91.7m3/s ore.
5.7m3/s of it is from T2 mining drones
33.3m3/s of it is from Porpoise boosts
If a Porpoise is boosting my yield by 57%, is it fair that I only give a sixth of that extra ore to the Porpoise?
Choice
Right now players have a choice to pay any value they want, half of the extra earnings or even nothing to the Porpoise pilot. While ‘compensation drones’ are still technically a choice your suggestion hard-codes the compensation to the boosting pilot to donate a value determined by your mining drone skill instead of a free choice.
Combat
Whenever NPCs appear you stop compensating the boosting ship with your drones when you swap them out for combat drones, even though it continues to boost your ship and you continue to mine ore.
Is that fair?
Skills
Imagine two beginning miners. One already has good mining drone skills and no T2 equipment yet. The other has good lasers but no good mining drones.
As a result the mining drone miner will be ‘compensating’ a much bigger portion of their income to the boosting ship than the miner with good laser skills, because compensation scales with mining drone yield rather than total yield. Is that fair?
Personally I think it’s easier to just give the boosting pilot some ISK or ore as compensation, this way players have all the choice how much they want to pay, and the compensation doesn’t depend on skill levels.
Or if you don’t want to deal with compensation, have someone with multiple pilots sit in the Porpoise or Orca. Multiboxing happens often in EVE, especially for miners. If someone has a few mining ships on the asteroid field already they’re already compensated if they have 2 other miners in fleet. Anyone else benefiting from the boosts is just lucky - but feel free to send ISK to the booster nonetheless!